CVE-2026-25536

HIGHPre-NVD 7.17.1
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to the CVSS score beside it.

This high-severity CVE scores 7.1 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.4% (30th percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from a secondary CVSS source
Sources: EPSS, a secondary CVSS source
Trending — 3 sources updated this week
7.1EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.4%CVSS: 7.1Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

MCP TypeScript SDK is the official TypeScript SDK for Model Context Protocol servers and clients. From version 1.10.0 to 1.25.3, cross-client response data leak when a single McpServer/Server and transport instance is reused across multiple client connections, most commonly in stateless StreamableHTTPServerTransport deployments. This issue has been patched in version 1.26.0.

CVSS v3
7.1
EG Score
7.1HIGHmedium confidence
EG Risk
32
EG Risk 32/100

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed (value × EchelonGraph’s weight)
Severity71% × 45%
The EG Score, 7.1 of 10.
Exploitation0.4% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at every mission impact level.
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.4%
EPSS %ILE
30th
KEV
Not listed

SSVC (CISA's decision table, applied by EchelonGraph)Track at every mission impact level.

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

February 4, 2026

Last Modified

July 15, 2026

Advisory Details (7)

Auto-updated Jul 15, 2026
Patch available. Sources: github, redhat.
Red HatMentions a patch (unverified)
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-25536.json
Red Hat

2436937 – (CVE-2026-25536) CVE-2026-25536 @modelcontextprotocol/sdk: @modelcontextprotocol/sdk cross-client data leak

https://bugzilla.redhat.com/show_bug.cgi?id=2436937
Red HatMentions a patch (unverified)

cve-details

https://access.redhat.com/security/cve/CVE-2026-25536
Red HatMentions a patch (unverified)
https://access.redhat.com/errata/RHSA-2026:3960
GitHub advisoryMentions a patch (unverified)

Sharing server/transport instances can leak cross-client response data · Advisory · modelcontextprotocol/typescript-sdk · GitHub

https://github.com/modelcontextprotocol/typescript-sdk/security/advisories/GHSA-345p-7cg4-v4c7
Web page

How to use MCP client in a multi-user application? · Issue #243 · modelcontextprotocol/typescript-sdk · GitHub

https://github.com/modelcontextprotocol/typescript-sdk/issues/243
Web page

Multiple clients to the same SSE connection? · Issue #204 · modelcontextprotocol/typescript-sdk · GitHub

https://github.com/modelcontextprotocol/typescript-sdk/issues/204

Vendor Advisories for CVE-2026-25536(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(1)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
redhatansible-automation-platform-tech-preview/mcp-server-rhel9:17721962222026-03-06redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(1 across 1 ecosystem)
npm(1)
PackageVulnerable rangeFix by version rangeDependents
@modelcontextprotocol/sdk—
  • 1.10.0 up to 1.26.0: fixed in 1.26.0
—

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 12× in last 7d / 28× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

Showing the most recent 94 of 184 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. 6 repeat rows among the latest 100 are merged into the row they repeat. The 90 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-14 16:32 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  2. 2026-10-13 16:33 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  3. 2026-10-12 16:33 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  4. 2026-10-12 16:19 UTCEG score recompute
  5. 2026-10-11 20:01 UTCEG score recompute
  6. 2026-10-11 17:14 UTCEG score recompute
  7. 2026-10-11 14:46 UTCEG score recompute
  8. 2026-10-11 13:48 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  9. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  10. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  11. 2026-10-09 09:28 UTCOSV refresh
  12. 2026-10-08 17:11 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  13. 2026-10-07 23:47 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  14. 2026-10-06 15:17 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  15. 2026-10-05 17:42 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  16. 2026-10-04 23:21 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  17. 2026-10-03 14:25 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  18. 2026-10-01 19:49 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  19. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  20. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  21. 2026-09-26 15:58 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  22. 2026-09-26 00:26 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  23. 2026-09-24 14:03 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  24. 2026-09-20 20:15 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  25. 2026-09-19 17:00 UTCOSV refresh
Show 69 more
  1. 2026-09-18 19:27 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  2. 2026-09-16 14:07 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  3. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  4. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  5. 2026-09-12 15:01 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  6. 2026-09-11 14:52 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  7. 2026-09-10 09:34 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  8. 2026-09-08 22:00 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  9. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  10. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  11. 2026-09-04 05:06 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  12. 2026-09-02 14:11 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  13. 2026-09-01 13:53 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  14. 2026-09-01 04:39 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  15. 2026-08-31 20:05 UTCOSV refresh
  16. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  17. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  18. 2026-08-28 21:41 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  19. 2026-08-27 14:25 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  20. 2026-08-26 14:46 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  21. 2026-08-25 13:48 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  22. 2026-08-23 00:19 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  23. 2026-08-21 23:49 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  24. 2026-08-20 22:55 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  25. 2026-08-19 17:03 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  26. 2026-08-18 13:48 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  27. 2026-08-17 13:47 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  28. 2026-08-16 14:56 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  29. 2026-08-16 02:14 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  30. 2026-08-15 01:30 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  31. 2026-08-14 23:02 UTCVendor advisory
  32. 2026-08-14 11:10 UTCEG score recompute
  33. 2026-08-14 11:10 UTCVendor advisory
  34. 2026-08-13 22:00 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  35. 2026-08-13 03:29 UTCEG score recompute
  36. 2026-08-13 03:29 UTCVendor advisory
  37. 2026-08-12 13:50 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  38. 2026-08-11 13:42 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  39. 2026-08-11 00:00 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  40. 2026-08-10 03:42 UTCVendor advisory
  41. 2026-08-09 15:49 UTCEG score recompute
  42. 2026-08-09 15:49 UTCVendor advisory
  43. 2026-08-09 13:46 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  44. 2026-08-08 16:37 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  45. 2026-08-07 22:45 UTCEG score recompute
  46. 2026-08-07 22:45 UTCVendor advisory
  47. 2026-08-06 13:46 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  48. 2026-08-06 04:21 UTCEG score recompute
  49. 2026-08-06 04:21 UTCVendor advisory
  50. 2026-08-05 19:17 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  51. 2026-08-04 15:10 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  52. 2026-08-03 10:36 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  53. 2026-08-02 21:24 UTCEG score recompute
  54. 2026-08-02 21:24 UTCVendor advisory
  55. 2026-08-02 02:26 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  56. 2026-08-01 04:16 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  57. 2026-07-30 22:51 UTCOSV refresh
  58. 2026-07-30 16:27 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  59. 2026-07-30 01:30 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  60. 2026-07-28 15:36 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  61. 2026-07-26 14:54 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  62. 2026-07-25 14:17 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  63. 2026-07-24 14:17 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  64. 2026-07-23 14:18 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  65. 2026-07-23 03:07 UTCEG score recompute
  66. 2026-07-22 14:08 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  67. 2026-07-20 17:08 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  68. 2026-07-19 14:31 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  69. 2026-07-19 02:28 UTCEPSS rescoreEPSS 0.3% · 18th percentile

Related CVEs(same product + same vendor + same CWE)

Same product

3 shown

npm:@modelcontextprotocol/sdk

Frequently asked(5)

What is CVE-2026-25536?
CVE-2026-25536 is a high-severity vulnerability; its CVE record was published on February 4, 2026. MCP TypeScript SDK is the official TypeScript SDK for Model Context Protocol servers and clients. From version 1.10.0 to 1.25.3, cross-client response data leak when a single McpServer/Server and transport instance is reused across multiple client connections, most commonly in stateless…
When was the CVE record for CVE-2026-25536 published?
The CVE record for CVE-2026-25536 was published on February 4, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of July 15, 2026; the record at its source may have been updated since.
Is CVE-2026-25536 actively exploited?
CVE-2026-25536 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.4% probability of exploitation in the next 30 days (30th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-25536?
CVE-2026-25536 has a CVSS base score of 7.1 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-25536?
A fix for CVE-2026-25536 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-25536 are linked in the Vendor Advisories panel on this page.

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